Steam boiler and process of firing it



June 14, 1932. AQ E, UCKE 1,863,541

STEAII BOILER AND PROGESS OF PIRING IT Filed Dec. 10'. 1927 2 Sheets-Sheet l INVENTO j im! W' ATToRNEYa June 14, 1932. c; E. LucKE 1,863,541

STEAK BGH-1ER AND PROCESS 0F FIRING IT vFiled Dec, 10', 1927 2 Sheets-Sheet 2 r BY Wr rbd/ n ATTORNEYS leaving the the form shown these gases Parenteel June 14, 1932 CHARLES E. LUCKE, OF N EW YORK, N. Y., ASSIGNOR TO N11-ED STATES PATENT OFFICE THE BABCOCK & WILCOX COM- PANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY STEAM BOILER AND PROCESS FIRING- IT Application filed December 10, 1927. Serial No. 239,099.

This invention relates to a steam boiler that4 is provided with a mechanical stoker and t0 the process of ring the boiler so that it can be operated at high ratings without overheating the stoker and especially with heated air. The invention will be understood from the description in connection with the accompanying drawings, in which Fig. 1 is a vertical section showing somewhat diagraminatically an illustrative embodiment of the invention, Fig. 2 is a section on an enlarged scale along the line 2-2 of Fig. 1; Fig. 3 is a section along the line 3 3 of Fig. 2 and Fig. 4 is a vertical section, partly broken away, illustrating a modification.

1n the drawings, reference character 1 indicates the furnace of a boiler that is provided with a. chain grate stoker 2. The exit for waste gases is shown at 3 and leads to an air heater 4 from which a conduit 5 leads to the stack. The cold air enters the air heater 4 at 6, and heated air passes out through a conduit 7 that is provided with a damper 8.

A humidifier lOor air is provided, and heat in the waste products of combustion air heater 4 is utilized for heating water to humidity the air in the humidiiier. The humidifier is provided Wih a separator 11 to remove unvaporized drops of water from the sprays 12. The heat for vaporization is derived from iiue gases, and in heat thewater to be sprayed into the air. A sump 13 is provided in the lower portion of the humidifier,

` and water is fed to the sump 13 through the pipe 14 with a iioat valve 15v for keeping the proper water level therein and to replace the evaporated water. A ump 16 forces water from the sump 13 through the heating coil 17 located in the waste `gas conduit 5.

A fan or blower 20 forces air into the humidiiier where it becomes saturated with moisture at an elevated temperature and this iixes the weight of water vapor carried. The heated saturated air passes through the outlet 21 that is provided with a damper 22 and joins the hot air from the outlet 7, and the mixture passes through the conduit 23 into the spaces below the stoker 2. Adjustment of relative position of dampers 8 and 22 determines the temperature of the air delivered to the stoker and also the amount of water vapor carried by that air. This adjustment also determines what part of the boiler wasteheat is utilized for raising the temperature of the air and what part for vaporizing water. A plurality obranches 25, each provided with a valve 26, leads from the conduit 23 to thecompartments 28 of. the chain grate stoker. The compartments 28 are provided in a` well known manner to divide the space under the chain grate Stoker into sections, and the amount of air admitted to each section can be regulated by means of the dampers 26.

In the modiiication shown in Fig. 4, air of one condition as to perature is admitted through the conduit 7 and passes through branches 25 that are provided with dampers 26', into some of the compartments 28 of the chain grate Stoker. Air that contains more from a humidiiier is deliveredthrough the injector nozzle 33 and draws in air of less humidity from conduit 3l producing a mixture in conduit 34 of higher humidity for one of the stoker compartments than is supplied through conduit 7 to the others. The air supplied to 7 and 33 may be the same as, for example, that from the air heater, or it may be dierent as to temperature and moisture. It may be supplied from another hu- In the modification shown in Fig. 4, the humidified airis indicated as being led to thekiirst compartment of the series of compartments 28, but the conduits and dainpers be arranged to give a diii'erent distribuhumidity and temmoisture obtained very hot furnaces and especially when using preheated air. The presence of the moisture in the air causes the formation of water gas when this moisture strikes the lower layers of highly heatedV coal bed nearest to the metal parts, and the endothermic reaction with the coke that results absorbs heat and lowers the temperature of this zone and the metal parts beneath it. The Water gas thus produced undergoes combustion within the furnace so that the heat is not lost. Without this temperature control of the metal parts of the stoker the allowable air temperature cannot-be high enough to give the best possible efficiency to the boiler unit by return Aof its waste heat, land with my invention it is possible to use hotter air than would otherwise be safe and thereby vvget higher boiler plant eiciencies. v

I claim: 1. The hereindescribed method of operating a Stoker ire furnace, which includes the steps of introducing through the Stoker, 'and distributing throughout the area of incandescence adjacent the stoker, an air mixture humiditied only to the required degree for producing an endothermic reaction forming Water gas and cooling the hotter portion of the Stoker area, and consuming the Water gas.'

2. The hereindescribed method of operating a stoker fired furnace which includes the steps of introducing through the stoker and distributing throughout the area of incandescence adjacent the Stoker a mixture of heated, and relatively unheated humidiied air combined in proportionsto preserve only the requisite degree of humidification for producing an endothermic reaction forming lwater gas and cooling the hotter portion of the Stoker area, and consuming the Water gas.

3. In combination with a furnace and stoker, an air heater supplying some air to the incandescent area adjacent the stoker, a humidiying air supply means also supplying air to the aforesaid area, and means regulating the air supplies to retain only the requisite humidity to produce alrelidothermic reaction profducing water gas at the aforesaid incandescent area to cool the hotter portion of the Stoker. W 4. The hereindescribed method of operat- 'ing an endless chain grate stoker fired fur'- nace with high temperatures therein, which includes the steps of introducing through I the Stoker, and distributing throu hout the area of incandescence of-.the fuel edadjacent the feed end of the Stoker, a preheated air mixture humldified to the'degree required for producing an endothermic reaction form- L ing water gas and thereby limiting the tem- J perature ofy the adjacent portion of the fuel bed'and cooling the adjacent portion of the Stoker, and consuming the water gas so l formed in the furnace. 1..; Y p CHARLES E. LUCKE. 

